Coagulation monitoring devices are used to test a patient's blood before, during and after procedures such as cardiac surgery, cardiovascular surgery, cardiac catheterization, electrophysiology, extracorporeal membrane oxygenation, hemodialysis, etc., to test the patient's response to anti-coagulant medications such as:                Heparin        Vitamin K antogonists such as Warfarin (Coumadin)        Novel oral anticoagulants such as dabigatran, rivaroxaban, and apixaban.        
Anticoagulants are a class of drugs that work to prevent coagulation (clotting) of blood. It is important for each patient to be administered the amount and type of anti-coagulant that is appropriate for his/her individual physiology. Too large an amount of anticoagulants can cause uncontrolled bleeding. Too small an amount of anticoagulants can cause thrombosis (blood clotting), which can lead to heart attack (acute myocardial infraction), or stroke.
Some known point-of-care (POC) coagulation monitoring devices operate by pumping a predefined quantity of blood from a sample well into a test chamber of a cuvette. The test chamber of the cuvette can contain an activator such as silica, kaolin, diatomaceous earth, etc. Once in the test chamber, the pump can move the sample back and forth at a predetermined rate and monitor for clot formation. For example, optical detectors can be operable to detect a decrease in sample mobility, which can be indicative of clot formation.
Known POC coagulation monitoring devices suffer from a number of deficiencies, including inaccurate pumps, high pump current draw, excess pump heat, and difficulties visualizing clot formation. Clotting time measurement is a critical measurement in a number of scenarios, including treatment of stroke victims and pre-operative care. Therefore, a need exists for improvements in coagulation monitoring devices.
Platelet function tests are used to assess the ability of a patient's platelets to be activated via a specific pathway. This allows a medical professional to evaluate a patient's response to P2Y12 inhibitors such as thienopyridine's including clopidogrel (Plavix®) and prasugrel (Effient®) which are prescribed in cases of acute coronary syndrome (ACS) such as heart attack (acute myocardial infarction) and chest pain (angina). Platelet function tests can also measure activation from a variety of agonists such as arachidonic acid, epinephrine, collagen, etc.
Some known POC platelet function devices operate by pumping a predefined quantity of blood from a blood tube into one or more test chambers. These devices may be turbidimetric based optical detection systems, which measure platelet induced aggregation. For example, each test chamber can be imaged via an independent optical sensor illuminated by a dedicated emitter. The reagent is formulated to measure platelet aggregation mediated by a specific pathway (P2Y12, Arachadonic Acid, llb/llla). Light transmittance increases as activated platelets bind and aggregate fibrinogen coated beads. The instrument measures this change in optical signal and reports results in test specific Reaction Units (PRU, ARU, or PAU).
Known POC platelet function devices suffer from deficiencies similar to those described above with reference to POC coagulation monitoring devices, including inaccurate pumps, high pump current draw, excess pump heat, and difficulties visualizing platelet aggregation. Individual response to p2Y12 inhibitors is variable and adequate platelet inhibition is not assured using a common empirical dose. For example, the literature reports as many as 30% of patients do not respond to Plavix. Platelet function testing is therefore a critical measurement to ensure that each patient receives an effective dose of appropriate drugs. Therefore, a need exists for improvements in platelet function devices. In some instances, embodiments described herein can be suitable for improving platelet function devices and/or coagulation monitoring devices.